Milfoil Weevil - Is it the answer?

Can this little sesame seed sized aquatic beetle be the solution to our problem with Milfoil in our lakes? The Milfoil Weevil is very selective in its' choice of where to live and only targets Milfoil species. It eats the growing tip as well as burrowing through the stem and that is what kills the plant.

Photo from KLSA's Guide to the Watermilfoil Weevil

Studies are being done now in our area and hopefully they are able to address some of our Milfoil weed problems. The Milfoil Weevil is native to our area but the density (numbers) of them is not great enough to act as a weed control measure. Lake "seeding" is being done to study the effectiveness, but it is costly, so is only being done in smaller control areas.

Milfoil covered with Algae, photo by Jeff Chalmers

The simple answer seems to be if more Milfoil Weevils can survive over the winter months, there numbers may increase, and act as more of a natural weed control in our lakes. Natural shorelines with organic leaves, plants, etc. give the Weevil habitat for over winter and increase the chances of the population increasing over time.

Our area has several native species of Milfoil, the most common being the Northern species which usually doesn't grow in large patches. It is the Eurasian Milfoil which is an invasive species that we commonly see at the surface as a "nuisance". The Eurasian Milfoil was introduced to the Kawartha Lakes via the Great Lakes and shipping coming from Europe. Eurasian Milfoil (reddish top) has spread throughout our lakes and it seems to be the main culprit in our weed problems.

Eurasian Milfoil, photo by Jeff Chalmers

Northern Milfoil, photo by Kyle Borrowman

There is also a new "Hybrid" variety of the Northern and Eurasian varieties that has now been identified and can be as troublesome as the Eurasian variety.

Please Note: Milfoil is able to spread from fragments rooting and growing into new plants. Broken/cut pieces of Milfoil should be removed from the water so they can not spread the plant.